Electrode holder for electric furnaces



July 3, 1928. 1,675,742

F. WECKERLE ELECTRODE HOLDER FOR ELECTRIC FURNACES Filed Aug. 28, 1925 Unventor Bid/hand h ecfier/e,

Attorney. I

Patented Jay 3, 1928.

UNITED STATES PATENT OFFICE.

FERDINAND WECKERLE, OF MUNICH, GERMANY, ASSIGNOR T STUDIENGESELLSCHAFT FUER WIRTSCHAFT U. INDUSTRIE, M. B. H., 01 MUNICH, GERMANY.

ELECTRODE HOLDER FOR ELECTRIC FURNACES.

Application filed August 28, 1925, Serial No. 53,136, and in Germany September 5, 1924.

The arrangement of the known electric furnaces is generally such that the carbonholders as is the case for instance with the Heroult furnace'can only be lowered and raised. Such movements are sufficient to meet the requirements of this particular type of furnace. However it'such furnaces are to be utilized-for other purposes there is no possibility of adapting the same to such 1 usages without great changing and labour. Also in these furnaces the electrode-holders do not fit the walls in an air-tight manner. The few types of furnaces with air-tight fitting electrode-holders, among which the Fiat-furnaces seem to be the best, employ very complicated means which it is deemed unnecessary to explain in detail. It is the purpose of this invention to transform a normal Heroult-furnace into a radiationfurnace which is air-tight. The advantage of this construction consists in securing a minimum consumption of the electrodes, of avoiding any lateral conductors and transmitting members and to avoid therefore also 2 a burning of. the carbon-holders. It is customary to employ water-cooling and this kind of cooling is not to be dispensed .with in furnacesof such high temperatures as air-cooling would be quite ineffectual. The

3" present invention allows, above all, a universal movability of the electrode-holders. The annexed drawing represents as example in Fig. 1, a vertical longitudinal section and in Fig. 2, a plan view of electrode-holders 5 according to the present invention.

The universal moi-ability of the electrodeholders is obtained, as is shown in the drawing, by positioning the electrode-holder A in the spherical depression of a water-cooled pedestal a resting on the ceiling of the furnace. The spherical base 6 of carbon-holder A is likewise water-cooled and said holder is supported by trunnions c mounted in a gimbal 0 this construction allowing movability of the holder in planes perpendicular to each other with the gimbal a supported in the standards (Z. As an important fact it is to be mentioned that the inside of the carbon-holder is lined with a highly fire-proof enamel e the insulating properties of which are amply sufiicient for insulating the high voltages which are to be expected in such furnaces.

At the upper end of the carbon-holder A the carbon is held by a common stuffing-box,

with an asbestos cord packing f of square cross-section. Thereby an air-tight closing is secured and the same closing will also answer for any usual carbon electrodes. lVit-h regardto such carbon electrodes it must be stated that they are never manufactered uniformly with the same exact diameter and that there is always to be reckoned with an allowance of at least five per cent of the diameter. Also therectilinearity of such carbons shows always variations and deflections on their median portion. Such defects can be avoided by employin graphite electrodes because these can be turned and ground on a lathe while the carbon electrodes forbid such manipulations on account of their hardness. The difi'eronce of cost of the two kinds of electrodes however is so considerable, that the carbon electrodes are mostly preferred if the safety of working may be secured and this is the case with our arrangement.

In view of the fact that with the carbonholder as compared to the graphite-elec-. trode the conductibility is Very inferior the electric current would spark over into the iron of the carbon-holder at the upper end of the electrode and would leave the iron again at the lower end and would act de structively on these spots. A very rapid deterioration of the holder would result and the working could hardly be maintained for more than twenty minutes. This however is avoided by means of the above mentioned inner insulating enamel lining. The spherical part a besides may also be insulated from the furnace-walls by means of mica layers and on account of the watercooling also this part of the insulating will not risk any damage. The arrangement of the electrodes for passing through the fireproof brick work remains here as is usual in electric furnaces.

By the arrangement according to the present invention there is no need of insulating the carbon itself and it is well known that all experiments to do so have so far failed. Owing to the insulation of the carbon-holder according to this invention the current is only admitted above the insulating and the carbOn-electr0de will act now on its greater length as a moderating resistance.

I claim:

1. In a electrode-holder for electric turnaces and in combination a pedestal having on said carbon-holder and supported by said gimbal to permit swinging movements of said holder in planes perpendicular to each other, and a stuffing-box at the upper end of the carbon-holder adapted to secure an air-tight closing between carbon and holder.

2. In an electrode holder for electric furnaces, the combination of a pedestal having aspherical depression, a carbon holder having a spherical "bottom fitting into said depression and further having an inner wall provided with an insulating lining, and a mounting for said holder permitting of movements in planes perpendicular to each other and relative to said pedestal.

In an electrode holder for electric furnaces, a holder body having anopening therethrouglr for the reception of an electrode. and provided with an insulating coating of enamel in which. for the purpose of forming a continuous unit with the body,

the enamel is melted in said opening to form:

an integral part of said body which is thereby insulated against electric current and is heat conducting for cooling purposes.

In testimony whereof I allix my signature.

FERDINAND WECKERLE. 

